control theory

In the late 90s, Volkswagen aired a series of awesome television advertisements that won a few awards relevant to those in advertising circles. One of these ads was titled Synchronicity and showed a VW Jetta’s windshield wipers (among other things) syncing to music as the car drove down a rainy alley. [ch00f] thought beat tracking wipers would make for a great project, and we love the sheer amount of engineering that went into this build.

The build began with [ch00f] taking apart his wiper motor to get some specifics for his build. Ideally, a rotary encoder would be very useful for this project, but designing a durable encoder would be a pain anyway. [ch00f] had to settle with the ‘parking pins’ on the wiper gear motor that allow the wipers to be driven in intermittent mode.

[ch00f] spent a great deal of time writing code that would guarantee a constant wiper speed, but that didn’t solve the problem of phase, or having the wipers begin or end their cycle on the beat. This problem was somewhat solved (as you can see in the video after the break) by using a feed forward system – basically, the software would predict the change in phase needed and correct it by changing the speed.

The build still isn’t perfect, although that’s mainly due to the placement of wiper parking switch on the wiper motor. [ch00f] plans on spending a little more time correcting the wiper speed/phase control with software, but what he’s got now is still very impressive.